The goal of our proposed research is to provide a structural and biochemical account of the activities of Glugea stephani and G. hertwigi during growth within greatly hypertrophied host cells (xenomas). The ultimate goal is to identify the mechanisms by which these intracellular parasites alter host cell development and induce growth; in addition, we wish to determine what physiological principles enable the parasites to multiply to large numbers without causing host cell degeneration. It is likely that we can gather some important information about the general phenomenon of induced cell hypertrophhy caused by this peculiar group of intracellular parasites since we have access to two techniques which will enable us to deal with the endoparasites independently of the host cell development. Their association with the host cells offers great possibilities to the basic problems in cell biology mainly related to the induction of growth and differentiation. The objectives of our proposed research are to develop new knowledge about the activities of Glugea during the induction of altered development and hypertrophy of the host cells. The success of our proposal is predicated on the belief that our understanding of the physiological reactions between these intracellular parasites and host cells will be enhanced by efficient methods for isolating the endoparasites from the host cells without significantly altering the viability of the parasites. Information on the molecular activities of the parasites and the host cell will be characterized by ultrastructural and cytochemical techniques; and, with the use of isotopic labels, thin-layer chromatography and slab gel electrophoresis. Enzyme studies will provide us with some fundamental information about the metabolic capabilities of the parasites and the host cell component.